Correct AnsibleModule string type names to str

The valid type names can be found in
AnsibleModule._CHECK_ARGUMENT_TYPES_DISPATCHER, and any deviation
from those causes us to no longer be able to puppet any hosts. The
type name for strings is, courtesy of Ansible's implementation being
Python, "str".

Change-Id: Ia4d4cde9926f7506a864739b1b616438c5fe6f43

library/puppet_get_hiera_file_list

@@ -42,9 +42,11 @@ author: Monty Taylor
 def main():
     module = AnsibleModule(
         argument_spec=dict(
-            fqdn=dict(required=True, type='string'),
+            # See AnsibleModule._CHECK_ARGUMENT_TYPES_DISPATCHER for the
+            # names of valid types
+            fqdn=dict(required=True, type='str'),
             groups=dict(required=True, type='list'),
-            location=dict(required=True, type='string'),
+            location=dict(required=True, type='str'),
         ),
     )
     p = module.params